Method for configuring gain factors for uplink service in radio telecommunication system

ABSTRACT

A method for configuring gain factors in a WCDMA telecommunication system is provided in which the gain factor for defining power required for normal reception of uplink data in an environment supporting an uplink service over an E-DCH can be configured using minimal signaling information. First gain factors for first TFs corresponding to a part of a TF set including a plurality of TFs available for an uplink service are received. One of the first TFs is determined as a reference TF for a second TF other than the first TFs in the TF set. Then, a second gain factor for the second TF is calculated using the first gain factor for the determined reference TF. The second gain factor is used for transmitting or receiving uplink data.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.11/326,595, filed on Jan. 6, 2006, now pending, which in turns claimspriority under 35 U.S.C. §119(a) to applications entitled “Method forConfiguring Gain Factors for Uplink Service in Radio TelecommunicationSystem” filed in the Korean Industrial Property Office on Jan. 6 andFeb. 4, 2005 and assigned Serial Nos. 2005-0001400 and 2005-0010868,respectively. The contents of the foregoing described application arehereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a Wideband Code Division MultipleAccess (hereinafter referred to as “WCDMA”) telecommunication system.More particularly, the present invention relates to a method forconfiguring gain factors while reducing signaling overhead in anEnhanced Uplink Dedicated Channel (hereinafter referred to as “E-DCH” or“EUDCH”) for an uplink service.

2. Description of the Related Art

A Universal Mobile Telecommunication Service (hereinafter referred to as“UMTS”) system, which is a 3^(rd) generation mobile telecommunicationsystem based upon European mobile communication systems (i.e., GlobalSystem for Mobile Communications (GSM) and General Packet Radio Services(GPRS)) and employing a WCDMA scheme, provides uniform services whichenable cellular phone users or computer users to transmit packet-basedtext, digitized voice, video or multimedia data at a higher speed than 2Mbps no matter where they are located.

The UMTS system uses an E-DCH in order to further improve performance ofpacket transmission in a reverse communication, that is, an uplink (UL)communication from a User Terminal or User equipment (hereinafterreferred to as “UE”) to a Node B. In order to provide more stablehigh-speed data transmission, the E-DCH supports various techniques suchas Adaptive Modulation and Coding (hereinafter referred to as “AMC”),Hybrid Automatic Retransmission Request (hereinafter referred to as‘HARQ’), Node-B controlled scheduling, shorter Transmission TimeInterval (hereinafter referred to as “TTI”) length and so forth.

The AMC is a technique for improving resource use efficiency bydetermining a modulation scheme and a coding scheme for a data channelaccording to channel conditions between a Node B and a UE. A combinationof the modulation scheme and the coding scheme is called a Modulationand Coding Scheme (hereinafter referred to as “MCS”), and many MCSlevels may be defined according to supportable modulation schemes andcoding schemes. The AMC determines the MCS level according to channelconditions between a Node B and a UE, thereby improving the resource useefficiency.

The HARQ refers to a technique in which, when errors occur in aninitially transmitted data packet, the packet is retransmitted in orderto compensate for the erroneous packet. This HARQ may be classified intoa Chase Combining (hereinafter referred to as “CC”) technique and anIncremental Redundancy (hereinafter referred to as “IR”) technique. Inthe CC technique, packets having the same format as that at initialtransmission are retransmitted when errors occur. In the IR technique,packets having the different format than that at initial transmissionare retransmitted when errors occur.

The Node B-controlled scheduling is a scheme in which a Node Bdetermines whether to transmit uplink data on an upper limit value ofpossible data rates and transmits the determined information asscheduling allocation information to a UE when data is transmitted usingan E-DCH. In turn, the UE determines a possible data rate of an uplinkE-DCH with reference to the scheduling allocation information.

The shorter TTI length permits a TTI shorter than 10 ms corresponding toa minimum TTI of a typical Dedicated Channel (DCH), thereby reducingretransmission time and thus enabling high system throughput.

FIG. 1 is a view for explaining uplink packet transmission over an E-DCHin a typical radio telecommunication system. In the drawing, referencenumeral “100” designates a base station supporting an E-DCH service,that is, a Node B, and reference numerals “101”, “102”, “103” and “104”designate UEs using the E-DCH service. As shown in FIG. 1, the UEs 101,102, 103, 104 transmit data to the Node B 100 over E-DCHs 111, 112, 113,114, respectively.

Using data buffer statuses, requested data rates or channel conditioninformation of the UEs 101 to 104, the Node B 100 informs each UE 101 to104 of whether or not E-DCH data transmission is possible for thecorresponding UE or performs a scheduling operation for coordinatingE-DCH data rates. The scheduling is performed in such a manner thatlower data rates are assigned to UEs far away from the Node B 100 (forexample, the UEs 103, 104) and higher data rates are assigned to UEsnear to the Node B (for example, the UEs 101, 102), while a measuredNoise Rise or Rise over Thermal (hereinafter referred to as “RoT”) valueof the Node B does not exceed a target value in order to enhance theoverall system performance.

FIG. 2 is a message flowchart illustrating typicaltransmission/reception procedures over an E-DCH.

Referring to FIG. 2, in step 202, an E-DCH is set up between a Node Band a UE. This E-DCH setup is implemented through processes oftransmitting/receiving messages over a dedicated transport channel. Instep 204, the UE informs the Node B of scheduling information comprisingtransmission power information of the UE, which represents uplinkchannel conditions, information on transmission power margin which theUE can transmit, the amount of data, which are stacked up in a buffer ofthe UE and awaiting transmission, and so on.

In step 206, the Node B monitors scheduling information of a pluralityof UEs including the above-mentioned UE in order to schedule datatransmissions of the plurality of UEs. In step 208, using the schedulinginformation received from the UE, the Node B determines to grant packettransmission to the UE and transmits scheduling assignment informationto the UE. The scheduling assignment information comprises a granteddata rate and granted transmission timing.

In step 210, using the scheduling assignment information, the UEdetermines a Transport Format (hereinafter referred to as “TF”)signifying a transmission rate and transmission power of the E-DCH. TheUE transmits uplink packet data over the E-DCH according to the TF instep 214, and preferably simultaneously transmits the TF information tothe Node B in step 212. Here, the TF information comprises a TransportFormat resource Indicator (hereinafter referred to as “TFRI”)representing information on resources necessary for receiving the E-DCH.In step 214, the UE also selects a MCS level in consideration of thedata rate assigned by the Node B and channel conditions, and transmitsthe uplink packet data by using the MCS level.

In step 216, the Node B determines if errors occur in the TF informationand the packet data. In step 218, the Node B transmits NACK (NegativeAcknowledge) over an ACK/NACK channel when the determination proves bothor either of the TF information and the packet data to be erroneous, ortransmits ACK (Acknowledge) over the ACK/NACK channel when thedetermination proves both of the TF information and the packet data tohave no errors. The packet data transmission is completed and the UEtransmits new user data over the E-DCH when the Node B transmits theACK, but the UE retransmits packet data having the same contents asthose of the previously transmitted packet data over the E-DCH when theNode B transmits the NACK.

In the environment described above, the Node B improves the overallsystem performance by assigning lower data rates to UEs far away fromthe Node B that have worse channel conditions or are to be provided witha low priority data service, and assigning higher data rates to UEs nearto the Node B that have better channel condition or are to be providedwith a high priority data service.

TFs of an E-DCH, to which the Node B-controlled scheduling technique,the HARQ technique and the like are applied, are diversely configuredaccording to service types and data rates. The respective TFs define theoverall size of an E-DCH Transport Block (hereinafter referred to as“TB”) by the size and number data blocks, and thus represent individualdata rates different from each other. TF sets available for the E-DCHare configured such that they have various data rates in order toefficiently transmit a Protocol Data Unit (hereinafter referred to as“PDU”) transferred from an upper layer with as little padding aspossible. For example, the total number of TF sets for the E-DCH isabout 128 to 256.

FIG. 3 illustrates an example of typical TF configuration. As shown inthe drawing, TF Index (hereinafter referred to as “TFI”) 0 to TFI 11identifying TFs indicate TB size N_(info) in a range of 128 to 8192bits, respectively.

In order to transmit a transport channel for the E-DCH, a DedicatedPhysical Data Channel for E-DCH (hereinafter referred to as “E-DPDCH”)has been introduced in a physical layer. Power required to stablytransfer data over the E-DPDCH is determined by configuring a gainfactor representing a power ratio of the E-DPDCH to a Dedicated PhysicalControl Channel (hereinafter referred to as “DPCCH”), which is used as apilot channel.

The gain factor has different values from TF to TF because the amount ofoverall power requirement is different according to transmission rates.In other words, since data reception performance is determined bytransmission bit energy, that is, E_(b), packet transmission quality ofthe system is maintained only by keeping the transmission bit energyconstant. In order to keep the transmission bit energy constant, theamount of overall power requirement differs from transmission rate totransmission rate.

Hereinafter, a description will be given of a method for configuringgain factors for an uplink Dedicated Physical Data Channel (hereinafterreferred to as “DPDCH”), to which an uplink Dedicated Channel(hereinafter referred to as “DCH”) is mapped, on a TF-by-TF basis.

A network represented by a Radio Network Controller (hereinafterreferred to as “RNC”) configures transmission power, which is necessaryfor each TF to maintain constant quality, by using gain factors. A gainfactor configuration method is classified into a signaled gain factorscheme and a computed gain factor scheme. In the signaled gain factorscheme, the network informs a UE of TF-by-TF gain factors through upperlayer signaling. In the computed gain factor scheme, the network informsa UE only of gain factors for a reference TF Combination (hereinafterreferred to as “TFC”) representing a combination of reference TFs andtransport channels, and the UE personally calculates and determines gainfactors for the other TFs based on the gain factors for the referenceTFC.

The conventional computed gain factor scheme is expressed by thefollowing Equation (1). As described below, a ratio of a gain factor fora specific TFC to a gain factor for a reference TFC is given as a ratioof a transmission rate for a desired TFC and a transmission rate for thereference TFC:

$\begin{matrix}{A_{j} = {{\frac{\beta_{d,{ref}}}{\beta_{c,{ref}}} \cdot \sqrt{\frac{L_{ref}}{L_{j}}}}\sqrt{\frac{K_{j}}{K_{ref}}}}} & (1)\end{matrix}$

where, A_(j) denotes a power ratio of a DPDCH to a DPCCH for a desiredj-th TF. β_(d,ref) and β_(c,ref) denote a DPDCH gain factor and a DPCCHgain factor for a reference TF, respectively, L_(ref) denotes the numberof DPDCHs necessary for supporting a reference TFC, and L_(j) denotesthe number of DPDCHs necessary for transmitting a desired j-th TFC.K_(ref) and K_(j) denote transport channel data sizes for the referenceTFC and the j-th TFC, respectively, which are obtained as follows:

$\begin{matrix}{{K_{ref} = {\sum\limits_{i}{{RM}_{i} \cdot N_{i,{ref}}}}}{K_{j} = {\sum\limits_{i}{{RM}_{i} \cdot N_{i,j}}}}} & (2)\end{matrix}$

The transport channel data size is the sum of data bits of all transportchannels mapped to a corresponding physical channel. The data bits ofthe respective transport channels are not multiplexed together, but passthrough coding and rate matching according to weights of the respectivetransport channels and then are summated. A fraction of bits punched orrepeated by the rate matching is determined by a rate matching attributevalue RM disclosed through upper layer signaling. In Equation (2),RM_(i) denotes a rate matching attribute value of an i-th transportchannel, and N_(i,ref) and N_(i,j) denote data sizes after coding butbefore rate matching for the i-th transport channel. Therefore, K_(ref)and K_(j) become transport channel data size multiplexed after ratematching in a case of using the corresponding TFC.

Since a plurality of transport channels are mapped to one DPDCH, andthese transport channels have different coding rates and rate matchingratios, the gain factors are calculated using data sizes to which ratematching attribute values RM are applied as stated above.

Once a value of A_(j) representing the power ratio of the DPDCH to theDPDCCH is obtained in Equation (1), each gain factor can be derived fromthe value of A_(j). That is, a gain factor for the j-th TFC is asfollows:

If A_(j)>1, then β_(d,j)=1.0 and β_(c,j)=1/A _(j),

If A_(j)<=1, then β_(c,j)=1.0 and β_(d,j)=1/A _(j)  (3)

Both of the conventional gain factor configuration schemes require RadioResource Control (hereinafter referred to as “RRC”) signaling betweenthe UE and the RNC. In the signaled gain factor scheme, since all TFsneeded TF by TF are provided to the UE, significant signaling resourcesare consumed. Also, in the computed gain factor, the RNC must notify theUE of gain factors for the reference TFCs and information on therelationships between the respective TFCs and the reference TFCs throughRRC signaling. Accordingly, the computed gain factor scheme alsoconsumes significant signaling resources.

FIG. 4 illustrates information elements (hereinafter referred to as“IE”) of a signaling message for the conventional gain factorconfiguration. As shown in the drawing, IE “CHOICE Gain Factors” forgain factor choice comprises IE “Signaled Gain Factors” and IE “ComputedGain Factors”. In order to perform signaling of gain factors forreference TFCs, the IE “Signaled Gain Factors” comprises FDD and TDDfields representing whether a choice mode is a Frequency Division Duplex(FDD) mode or a Time Division Duplex (TDD) mode. When the choice mode isthe FDD, a DPDCCH gain factor β_(c), DPDCH gain factors β_(d) for therespective reference TFCs, and reference TFC IDs for the respective TFCsare also included in the IE “Signaled Gain Factors”. In addition, toapply the computed gain factor scheme to non-signaled TFCs, referenceTFC IDs corresponding to the respective TFCs are included in the IE“Computed Gain Factors”.

Accordingly, a need exists for a method for configuring gain factors ina WCDMA telecommunication system in which the gain factor for definingpower required for normal reception of uplink data in an environmentsupporting an uplink service over an E-DCH can be configured usingminimal signaling information.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve at least theabove-mentioned problems occurring in the prior art, and an object ofthe present invention is to provide a method for efficiently notifyinggain factors necessary for E-DCH transmission.

A further object of the present invention is to provide a method forreducing upper signaling overhead required to perform signaling ofreference TFCs necessary for gain factor calculation.

A further object of the present invention is to provide a method forusing only minimal information for notifying parameters needed todetermine E-DCH transmission power and for determining gain factorsnecessary for E-DCH transmission by using predefined rules.

In order to accomplish these objects, in accordance with one exemplaryaspect of the present invention, there is provided a method forconfiguring gain factors in a radio telecommunication system, the methodcomprising the steps of: receiving first gain factors for first TFscorresponding to a part of a TF set including a plurality of TFsavailable for an uplink service; determining one of the first TFs as areference TF for a second TF other than the first TFs in the TF set; andcalculating a second gain factor for the second TF by using the firstgain factor for the determined reference TF, the second gain factorbeing used for transmitting or receiving uplink data.

In accordance with another aspect of the present invention, there isprovided a method for configuring gain factors in a radiotelecommunication system, the method comprising the steps of: receivingfirst gain factors for first TFs corresponding to a part of a TF setincluding a plurality of TFs available for an uplink service; if anindex of a second TF other than the first TFs in the TF set is equal toor greater than a last index among indexes of the first TFs, determiningthe first TF having the last index as a reference TF for the second TF;if an index of a second TF other than the first TFs in the TF set isless than the last index, and the index of the second TF is equal to orgreater than a k-th index and is less than a (k+1)-th index of theindexes of the first TFs, determining the first TF having the k-th indexas the reference TF for the second TF; and calculating a second gainfactor for the second TF by using the first gain factor for thedetermined reference TF, the second gain factor being used fortransmitting or receiving uplink data.

In accordance with another exemplary aspect of the present invention,there is provided a method for configuring gain factors in a radiotelecommunication system, the method comprising the steps of: receivingfirst gain factors for first TFs corresponding to a part of a TF setincluding a plurality of TFs available for an uplink service; if anindex of a second TF other than the first TFs in the TF set is less thana first index among indexes of the first TFs, determining the first TFhaving the first index as a reference TF for the second TF; andcalculating a second gain factor for the second TF by using the firstgain factor for the determined reference TF, the second gain factorbeing used for transmitting or receiving uplink data.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view for explaining uplink packet transmission over an E-DCHin a radio telecommunication system;

FIG. 2 is a message flowchart illustrating typicaltransmission/reception procedures over an E-DCH;

FIG. 3 is a view FIG. 3 illustrating an example of typical TFconfiguration;

FIG. 4 is a view illustrating information elements of a signalingmessage for a conventional gain factor configuration scheme;

FIG. 5 is a view illustrating a scheme in which gain factors forremaining TFs are calculated using a gain factor for a reference TF inaccordance with an exemplary embodiment of the present invention;

FIG. 6 is a view illustrating information elements of a signalingmessage for gain factor configuration in accordance with an exemplaryembodiment of the present invention;

FIG. 7 is view illustrating a set of signaled gain factors in accordancewith a first exemplary embodiment of the present invention;

FIG. 8 is a view illustrating reference TFs configured in accordancewith the first embodiment of the present invention;

FIG. 9 is a flowchart illustrating an operation of configuring gainfactors of a UE in accordance with the first embodiment of the presentinvention;

FIG. 10 is view illustrating a set of signaled gain factors inaccordance with a second exemplary embodiment of the present invention;

FIG. 11 is a view illustrating reference TFs configured in accordancewith the second embodiment of the present invention;

FIG. 12 is a flowchart illustrating an operation of configuring gainfactors of a UE in accordance with the second embodiment of the presentinvention;

FIG. 13 is view illustrating a set of signaled gain factors inaccordance with a third exemplary embodiment of the present invention;

FIG. 14 is a view illustrating reference TFs configured in accordancewith the third embodiment of the present invention;

FIG. 15 is a flowchart illustrating an operation of configuring gainfactors of a UE in accordance with the third embodiment of the presentinvention;

FIG. 16 is view illustrating a set of signaled gain factors inaccordance with a fourth exemplary embodiment of the present invention;

FIG. 17 is a view illustrating reference TFs configured in accordancewith the fourth embodiment of the present invention; and

FIG. 18 is a flowchart illustrating an operation of a RNC in accordancewith an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed with reference to the accompanying drawings. It should benoted that the similar components are designated by similar referencenumerals although they are illustrated in different drawings. Also, inthe following description, a detailed description of known functions andconfigurations incorporated herein will be omitted for conciseness.

An important aspect of the present invention is to determine gainfactors necessary for power setup of a UE in order to transmit uplinkdata over an E-DCH. To this end, a Node B needs to know the power levelof the UE, and thus each of the UE and the Node B performs a gain factordetermination operation as will be described below. However, for theconvenience of explanation, the following description will be given onthe assumption that the UE sets up power.

Prior to explaining preferred embodiments of the present invention, adescription will be given first for an operation of using a reference TFand a gain factor corresponding to the reference TF for deriving gainfactors for the other TFs of the E-DCH. Since only one transport channelis used in the E-DCH, a TFC includes only one TF. Thus, in the followingdescription of preferred embodiments of the present invention, a term“TF” is used in place of a term “TFC”. However, it is to be understoodthat the TF in the E-DCH has the same meaning as that of the TFC.

In this specification, for the facilitation of explanation, a DPCCH gainfactor is assumed as an essentially constant value regardless of TFs. Ifthe DPCCH gain factor is essentially constant, the above-mentionedEquation (1) can be simplified as the following Equation (4). That is,it is unnecessary to relate the ratio of RMs to Equation (1) becauseonly one transport channel is used in the E-DCH, and the ratio of K_(j)and K_(ref) is simplified as a ratio of TB sizes. Thus, the followingEquation (4) can be used in the E-DCH:

$\begin{matrix}{\beta_{e,j} = {\beta_{e,{ref}}\sqrt{\frac{L_{ref}}{L_{j}}}\sqrt{\frac{N_{{info},j}}{N_{{info},{ref}}}}}} & \left( {{Eqn}.\mspace{14mu} 4} \right)\end{matrix}$

where, N_(info,j) denotes the TB size of a j-th TF, and N_(info,ref)denotes the TB size of a reference TF. If the DPCCH gain factor variesaccording to TFs, gain factors in Equation (4) can be regarded as aratio of power levels, and thus it is possible to set a gain factor ofone predetermined channel to 1 and to obtain gain factors of the otherchannels by using ratio values.

In addition, when several physical channels are used, a combination of achannelization code with a Spreading Factor (SF) of 2 and achannelization code with a SF of 4 can be used for the E-DCH, incontrast with the DPDCH using only one channelization code with a SF of4. As a result of this, simply considering the number of physicalchannels for a corresponding TF, the number of physical channels cannotbe discriminated SF by SF, so it is basically impossible to exactlycalculate the gain factors. Thus, in consideration of the E-DCHenvironment, the present invention converts an L value used in the gainfactor calculation into the equivalent number of physical channels forthe case of SF=4, and then applies the converted L value to the gainfactor calculation. In that case, the L value is as follows: if the SFis 2, L_(SF=2) is defined as twice of the number of original physicalchannels, and if not, L_(SF≠2) is defined as the number of originalphysical channels. Then, a gain factor in a case of SF=2 is obtained byapplying the equivalent number of physical channels L_(SF=2) to Equation(4) to derive a gain factor and applying the derived gain factor to anequation β_(e,SF=2)=√{square root over (2)}×β_(e,ref).

FIG. 5 illustrates an example in which, using a reference gain factorfor a signaled reference TF, gain factors for the remaining TFs arecalculated in accordance with an exemplary embodiment of the presentinvention. The first column of FIG. 5 denotes TFIs identifying TFs, thesecond column denotes TB sizes for the TFs, and the third column denotesoptimal gain factors capable of providing power required to satisfy agiven Block Error Rate (BLER) performance. Here in FIG. 5 are optimalgain factors which have been derived from simulation or field tests suchthat they satisfy 1% BLER performance.

In order to implement the computed gain factor scheme of the presentinvention, a reference gain factor is needed. Such a reference gainfactor is notified through upper signaling. That is, a gain factor=28for reference TFI 0 of 405 bits is provided to a UE through uppersignaling. When the DPCCH gain factor is fixed, only one transportchannel is used for the E-DCH, and the number of necessary DPDCHs is thesame, a gain factor of 32 is obtained by applying the computed gainfactor scheme of Equation (4) (Method 1) to a TF of 540 bits. It is seenthat the value “32” is the same as the optimal gain factor value shownin the third column of FIG. 5.

Similarly, if gain factors for all of the remaining TFs are derived byusing TFI 0 as the reference TF, gain factors as presented in the fourthcolumn of FIG. 5 are obtained. However, as seen from the fifth column ofFIG. 5, there are considerable errors in gain factors for TFI 2 to TFI10. This is because a low coding rate applied to small TB size requiresplenty of power, and thus unnecessary excess power is set up if a gainfactor for small TB size is used as a reference gain factor forobtaining gain factors for the other TFs. However, with TFs of TFI 13 orabove, errors decrease again. This is because an initial coding ratebecomes higher, and thus power required per information bit increasesagain.

Consequently, in a more improved computed gain factor scheme (Method 2)shown in the sixth column of FIG. 5, TFs are classified into a casewhere they belong to a TF set having a small coding gain, a case wherethey have general TB sizes, and a case where they require much morepower in a high coding rate, and separate reference TFs are set and usedfor the classified cases. The sixth and seventh columns of FIG. 5 showgain factors and their errors obtained using several reference TFs, thatis TFI 0, TFI 2 and TFI 11. It can be seen from the seventh column thaterrors significantly decrease.

When several reference TFs are used as stated above, gain factors fordesired TFs can be calculated with small errors. In a case of the DCH, aplurality of reference TFs are configured, and the correspondingreference TFs for all available TFs are provided to a UE to calculategain factors for desired TFs. However, in a case of the E-DCH, it ispossible to have a neighboring reference TF of signaled reference TFs asa reference TF to calculate optimal gain factors without separatelysignaling reference TFs for all available TFs.

If required power changes due to small TF size, a high initial codingrate or the like, errors occur in a gain factor. In this case, if a TFlocated in a boundary region of the power alteration is set as areference TF, TFs neighboring the reference TF have little error ascompared with optimal gain factors. This tendency is due to the factthat, in contrast with the UL DCH, the E-DCH consists of one transportchannel, and thus TFs of a TF set are arranged according to TB sizes.

Therefore, in an exemplary embodiment of the present invention, it isprearranged that reference TFs for all TFs of the E-DCH are notseparately notified to a UE, and one of signaled reference TFs is usedas a reference TF for each non-signaled TF. Consequently, there is noneed to separately notify a reference TF necessary for calculating again factor for each TF, so upper signaling overhead can be reduced.That is, the UE determines a reference TF for a TF chosen for the E-DCHby using predefined rules. At this time, the UE uses a signaled gainfactor for the determined reference TF for calculating a gain factor forthe chosen TF.

When the computed gain factor scheme is used according to the exemplaryembodiment of the present invention as stated above, the UE need not mapand notify reference TFs for all TFs, and thus IEs of a RRC signalingmessage for gain factor configuration is simplified as shown in FIG. 6.Referring to FIG. 6, IE “CHOICE Gain Factors” for gain factor choicecomprises IE “Signaled Gain Factors” and IE “Computed Gain Factors”. Inorder to perform signaling of gain factors for reference TFs, the IE“Signaled Gain Factors” comprises FDD and TDD fields representingwhether a choice mode is a FDD mode or a TDD mode. When the choice modeis the FDD, a DPDCCH gain factor β_(c) and E-DPDCH gain factors β_(e)for the respective reference TFs are also included in the IE “SignaledGain Factors”. β_(c) is a gain factor for a control section of anE-DPCCH or a Physical random Access Channel)/PCPCH (Physical Commonpacket Channel (PRACH) in a case of the FDD, and β_(e) is a gain factorfor a data section of the E-DPCCH or the PRACH/PCPCH in a case of theFDD or for all uplink channels in a case of the TDD. Here, IE “ComputedGain Factors” for the computed gain factor scheme is included in themessage only for representing the use of the computed gain factorscheme, and includes no additional information.

The UE acquires gain factors for TFs through the above-mentioned RRCsignaling message. Thereafter, in order to calculate a gain factor for aTF chosen for the E-DCH, the UE selects one of the signaled TFs, whichcorresponds to the chosen TF, as a reference TF. Similarly, a Node Bselects one of the signaled TFs, which corresponds to a TF notified fromthe UE over the E-DPCCH, as a reference TF in order to calculate a gainfactor for the notified TF. A gain factor for the reference TF is usedfor calculating the gain factor for the chosen or notified TF. As anexample, the Node B and the UE calculate a gain factor for a TF to beused by using the signaled TFs at every E-DCH transmission. As anotherexample, the Node B and the UE previously calculate gain factors for allTFs of a TF set and store in a memory, and can read out a TF chosen forthe E-DCH and a pre-calculated gain factor corresponding to the chosenTF from the memory and the use them.

Hereinafter, specific embodiments for choosing a reference TF will bedescribed in further detail. In the following description, for theconvenience of explanation, TFs gain factor of which have been acquiredthrough a RRC signaling message will be referred to as “signaled TFs”,and one TF chosen among them will be referred to as a “reference TF”.Thus, it is to be understood that all the signaled TFs may become thereference TFs.

Example 1

In Example 1, when it is intended to use the computed gain factorscheme, a TF is chosen for the E-DCH, and a signaled TF nearest to thechosen TF, from among signaled TFs having smaller TFIs or TB sizes thanthat of the chosen TF, is selected as a reference TF.

A TF set comprising of 18 TFs as stated above in connection with FIG. 5is used for explaining this Example. Of such a TF set, gain factors for3 TFIs, that is, TFI 0, TFI 2 and TFI 11 are notified as shown in FIG.7.

Referring to FIG. 7, the first column denotes Indicators successivelyassigned to signaled TFs, that is, k, the second column denotes originalindicators of the signaled TFs, that is, RTFI(k), third column denotesthe TB sizes of the signaled TFs, and the fourth column denotes gainfactors for the signaled TFs. In this way, only by signaling gainfactors for some TFs, that is, TFI 0, TFI 2 and TFI 11, a UE canconfigure a reference TF for each TF from TFI 1, a gain factor of whichis not signaled, to calculate its gain factor by using the reference TF.

If it is intended to derive a gain factor for TFI 1, RTFI(0)=0 of thesignaled TFs, which is smaller than TFI 1 and simultaneously is nearestto TFI 1, becomes a reference TF for TFI 1. Similarly, in a case of TFI3, RTFI(1)=2, which is smaller than TFI 3 and simultaneously is nearestto TFI 3, becomes a reference TF for TFI 3. By applying the sameprinciple to all TFs included in the TF set, reference TFs for therespective TFs are selected as in FIG. 8.

As shown in FIG. 8, TFIs 0, 2 and 11 are the signaled TFs, the otherTFIs are mapped to reference TFIs representing corresponding referenceTFs, respectively. Here, if Ref_TFI_i denotes a reference TFI selectedfor an i-th TF, Ref_TFI_1 is TFI 0=RTFI(0), Ref_TFI_3 to Ref_TFI_10 areTFI 2=RTFI(1), and Ref_TFI_12 to Ref_TFI_17 are TFI 11=RTFI(2). Gainfactors for the non-signaled TFIs are calculated according to a gainfactor for the corresponding reference TFI.

FIG. 9 is a flowchart illustrating an operation of configuring gainfactors of a UE in accordance with Example 1 of the present invention.In all of the exemplary embodiments of the present invention, a UEstores a TF set, which is prearranged between the UE and a network, andcomprises TFs available for the E-DCH between the UE and a network.

Referring to FIG. 9, in step 300, the UE receives gain factor values formaxK TFs from the network through RRC signaling. Here, RTFI denotesindexes of the signaled TFs, and are represented by RTFI(0) toRTFI(maxK−1). In step 302, in order to calculate a gain factor for eachTF of the overall TF set, the UE repeats steps 304 and 314 as many astimes corresponding to the number of the TFs of the TF set whileincreasing i one by one from 0. Here, i is an integer equal to orgreater than 0 and smaller than the number of TFs of the overall TF set.At this time, since gain factors for TFIs the same as the RTFIs havebeen already provided to the UE in step 300, step 302 may be omitted forthem.

First, in step 304, the UE determines if TFI_i indicating an i-th TFI isgreater than the maximum reference TFI, that is, RTFI(maxK−1). If so,the UE proceeds to step 306 to set Ref_TFI_i indicating a reference TFIcorresponding to TFI_i to RTFI(maxK−1). In next step 308, in order tocompare TFI_i with maxK RTFIs, the UE repeats step 310 as many as(maxK−1) times while increasing k one by one from 0. Here, k is aninteger equal to or greater than 0 and smaller than maxK−1. In step 310,the UE determines if TFI_i is equal to or greater than RTFI(k) and issmaller than RTFI(k+1). If TFI_i is equal to or greater than RTFI(k) andis smaller than RTFI(k+1) for a specific k, Ref_TFI_i is set to RTFI(k)in step 312.

In step 314, the UE calculates a gain factor for TFI-i by applying thegain factor for Ref_TFI_i, determined for TFI-i, to Equation (4). Here,the gain factor for TFI-i represented by Ref_TFI_i corresponds toβ_(e,ref) in Equation (4).

In step 316, the UE transmits E-DCH data according to the gain factorscalculated in step 310 or signaled in step 300.

Example 2

In Example 2, when it is intended to use the computed gain factorscheme, a TF is chosen for the E-DCH, and a signaled TF nearest to thechosen TF, from among signaled TFs having greater TFIs than that of thechosen TF, is selected as a reference TF.

A TF set comprising of 18 TFs as stated above in connection with FIG. 5is used for explaining this Example. Of such a TF set, gain factors for3 TFIs, that is, TFI 1, TFI 10 and TFI 17 are notified as shown in FIG.10.

Referring to FIG. 10, the first column denotes Indicators successivelyassigned to signaled TFs, that is, k, the second column denotes originalindicators of the signaled TFs, that is, RTFI(k), third column denotesthe TB sizes of the signaled TFs, and the fourth column denotes gainfactors for the signaled TFs. In this way, only by signaling gainfactors for some TFs, that is, TFI 1, TFI 10 and TFI 17, a UE canconfigure a reference TF for each TF from TFI 0, a gain factor of whichis not signaled, to calculate its gain factor by using the reference TF.

If it is intended to derive a gain factor for TFI 0, RTFI(0)=1 of thesignaled TFs, which is greater than TFI 0 and simultaneously is nearestto TFI 0, becomes a reference TF for TFI 0. Similarly, in a case of TFI2, RTFI(1)=10, which is greater than TFI 2 and simultaneously is nearestto TFI 2, becomes a reference TF for TFI 2. By applying the sameprinciple to all TFs included in the TF set, reference TFs for therespective TFs are selected as in FIG. 11.

As shown in FIG. 11, TFIs 1, 10 and 17 are the signaled TFs, the otherTFIs are mapped to reference TFIs representing corresponding referenceTFs, respectively. Here, if Ref_TFI_i denotes a reference TFI selectedfor an i-th TF, Ref_TFI_0 is TFI 1=RTFI(0), Ref_TFI_2 to Ref_TFI_9 areTFI 10=RTFI(1), and Ref_TFI_11 to Ref_TFI_16 are TFI 17=RTFI(2). Gainfactors for the non-signaled TFIs are calculated according to a gainfactor for the corresponding reference TFI.

FIG. 12 is a flowchart illustrating an operation of configuring gainfactors of a UE in accordance with Example 2 of the present invention.Here, a UE stores a TF set prearranged between the UE and a network.

Referring to FIG. 12, in step 400, the UE receives gain factor valuesfor maxK TFs from the network through RRC signaling. Here, RTFI denotesindexes of the signaled TFs, and are represented by RTFI(0) toRTFI(maxK−1). In step 402, in order to calculate a gain factor for eachTF of the overall TF set, the UE repeats steps 404 and 414 as many astimes corresponding to the number of the TFs of the TF set whileincreasing i one by one from 0. Here, i is an integer equal to orgreater than 0 and smaller than the number of TFs of the overall TF set.At this time, step 402 may be omitted for TFIs the same as RTFIs in step400.

In step 404, the UE determines if TFI_i indicating an i-th TFI is equalto or smaller than RTFI(0) indicating the minimum reference TF. If so,the UE proceeds to step 412 to set Ref_TFI_i indicating a reference TFIof TFI_i to RTFI(0). On the contrary, if TFI_i is greater than RTFI(0)in step 404, the UE repeats step 408 as many as maxK times whileincreasing k one by one from 0 in step 406, in order to compare TFI_iwith maxK RTFIs. Here, k is an integer equal to or greater than 0 andsmaller than maxK−1. In step 408, the UE determines if TFI_i is greaterthan RTFI(k−1) and is equal to or smaller than RTFI(k). If TFI_i isgreater than RTFI(k−1) and is equal to or smaller than RTFI(k) for aspecific k, Ref_TFI_i is set to RTFI(k) in step 410.

In step 414, the UE calculates a gain factor for TFI-i by applying thegain factor for Ref_TFI_i, determined for TFI-i, to Equation (4).

In step 416, the UE transmits E-DCH data according to the gain factorscalculated in step 414 or signaled in step 400.

Example 3

In Example 3, when it is intended to use the computed gain factorscheme, a TF is chosen for the E-DCH, and a signaled TF nearest to thechosen TF, from among signaled TFs, is selected as a reference TF.

A TF set comprising of 18 TFs as stated above in connection with FIG. 5is used for explaining this Example. Of such a TF set, gain factors for3 TFIs, that is, TFI 1, TFI 6 and TFI 14 are notified as shown in FIG.13.

Referring to FIG. 13, the first column denotes Indicators successivelyassigned to signaled TFs, that is, k, the second column denotes originalindicators of the signaled TFs, that is, RTFI(k), third column denotesthe TB sizes of the signaled TFs, and the fourth column denotes gainfactors for the signaled TFs. In this way, only by signaling gainfactors for some TFs, that is, TFI 1, TFI 6 and TFI 14, a UE canconfigure a reference TF for each TF from TFI 0, a gain factor of whichis not signaled, to calculate its gain factor by using the reference TF.

If it is intended to derive a gain factor for TFI 0, RTFI(0)=1 of thesignaled TFs, which is nearest to TFI 0, becomes a reference TF for TFI0. Similarly, in a case of TFI 2, RTFI(0)=1, which is nearest to TFI 2,becomes a reference TF for TFI 2. In a case of TFI 10, since TFI 10 liesbetween RTFI(1)=6 and RTFI(2)=14 and has the same spacing from both ofthem, prearranged riles are applied. For example, if it is prescribedthat a lower RTFI is selected when spacing from both RTFIs is the same,a reference TF of TFI 10 becomes RTFI(1)=6. By applying the sameprinciple to all TFs included in the TF set, reference TFs for therespective TFs are selected as in FIG. 14.

As shown in FIG. 14, TFIs 1, 6 and 14 are the signaled TFs, the otherTFIs are mapped to reference TFIs representing corresponding referenceTFs, respectively. Here, if Ref_TFI_i denotes a reference TFI selectedfor an i-th TF, Ref_TFI 0, Ref_TFI_2 and Ref_TFI_3 are TFI 1=RTFI(0),Ref_TFI_4, Ref_TFI_5 and Ref_TFI_7 to Ref_TFI_10 are TFI 6=RTFI(1), andRef_TFI_11 to Ref_TFI_13 and Ref_TFI_15 Ref_TFI_17 are TFI 14=RTFI(2).Gain factors for the non-signaled TFIs are calculated according to again factor for the corresponding reference TFI.

FIG. 15 is a flowchart illustrating an operation of configuring gainfactors of a UE in accordance with Example 3 of the present invention.Here, a UE stores a TF set prearranged between the UE and a network.

Referring to FIG. 15, in step 500, the UE receives gain factor valuesfor maxK TFs from the network through RRC signaling. Here, RTFI denotesindexes of the signaled TFs, and are represented by RTFI(0) toRTFI(maxK−1). In step 502, in order to calculate a gain factor for eachTF of the overall TF set, the UE repeats steps 504 and 522 as many astimes corresponding to the number of the TFs of the TF set whileincreasing i one by one from 0. Here, i is an integer equal to orgreater than 0 and smaller than the number of TFs of the overall TF set.At this time, step 502 may be omitted for TFIs the same as RTFIs in step500.

In step 504, the UE compares TFI_i indicating an i-th TFI with RTFI(0)indicating the minimum reference TF. If TFI-i is equal to or smallerthan RTFI(0), the UE proceeds to step 512 to set Ref_TFI_i indicating areference TFI of TFI_i to RTFI(0). On the contrary, if TFI_i is greaterthan RTFI(0) in step 504, the UE compares TFI_i with RTFI(maxK−1)indicating the maximum reference TF. If TFI-i is greater thanRTFI(maxK−1), the UE proceeds to step 514 to set Ref_TFI_i toRTFI(maK−1). If TFI-i is greater than RTFI(0) and is equal to or smallerthan RTFI(maxK−1), the UE repeats step 510 as many as (maxK−1) timeswhile increasing k one by one from 0, as shown in step 508. Here, k isan integer equal to or greater than 0 and smaller than maxK−1.

In step 510, the UE determines if TFI_i is greater than RTFI(k) and isequal to or smaller than RTFI(k+1). If TFI_i is greater than RTFI(k) andis equal to or smaller than RTFI(k+1) for a specific k, the UE proceedsto step 516 to determine which of RTFI(k) and RTFI(k+1) is nearest toTFI-i. To this end, the UE compares a difference between TFI-i andRTFI(k) with a difference between TFI-i and RTFI(k+1). If{RTFI(k+1)-TFI-i} is greater than {RTFI(k)-TFI-i}, then Ref_TFI_i is setto RTFI(k) in step 518. In contrast, if {RTFI(k)-TFI-i} is greater than{RTFI(k+1)-TFI-i}, then Ref_TFI_i is set to RTFI(k+1) in step 520. Ifthe two differences are the same, then Ref_TFI_i is set to RTFI(k) instep 518. In an alternative example, Ref_TFI_i may be set to RTFI(k+1)if the two differences are the same.

In step 522, the UE calculates a gain factor for TFI-i by applying thegain factor for Ref_TFI_i, determined for TFI-i, to Equation (4).

In step 524, the UE transmits E-DCH data according to the gain factorscalculated in step 522 or signaled in step 500.

Various comparative methods applicable to Example 3 are presented in thefollowing Equations (5) to (7):

if log(TFI-i)−log(RTFI(k))=<log(RTFI(k+1))−log(TFI _(—) i)

Ref _(—) TFI _(—) i=RTFI(k)

else Ref _(—) TFI _(—) i=RTFI(k+1)  (5)

In Equation (5), a RTFI having a small difference between logarithmicvalues is selected.

if TB(TFI-i)−TB(RTFI(k))<TB(RTFI(k+1))−TB(TFI _(—) i)

Ref _(—) TFI _(—) i=RTFI(k)

else Ref _(—) TFI _(—) i=RTFI(k+1)  (6)

where, TB(TFI_i) denotes TB size corresponding to TFI_i. Thus, inEquation (6), a RTFI having a small difference between TB sizes isselected.

if log(TB(TFI-i))−log(TB(RTFI(k)))<log(TB(RTFI(k+1)))−log(TB(TFI _(—)i))

Ref _(—) TFI _(—) i=RTFI(k)

else Ref _(—) TFI _(—) i=RTFI(k+1)  (7)

In Equation (7), a RTFI having a small difference between logarithmicvalues of TB sizes is selected.

Example 4

In Example 4, a network, that is, a RNC notifies a UE of a gain factorfor a preset TF, and the UE calculates the other TFs by using the presetTF as a reference TF. The RNC chooses at least one TF per physicalchannel to have it as a reference TF, and predetermines reference TFs ofthe other TFs as TFs having the same number of physical channels. Also,in Example 4, one gain factor is set to reference gain factors for TFshaving the same number of physical channels, but another gain factor maybe used for TFs, initial coding rate of which is higher, from among theTFs having the same number of physical channels.

A TF set comprising of 18 TFs as stated above in connection with FIG. 5is used for explaining this Example. Of such a TF set, gain factors for5 TFIs, that is, TFI 0, TFI 4, TFI 6, TFI 9 and TFI 13 are notified asshown in FIG. 16.

Referring to FIG. 16, the first column denotes Indicators successivelyassigned to signaled TFs, that is, k, the second column denotes originalindicators of the signaled TFs, that is, RTFI(k), third column denotesthe TB sizes of the signaled TFs, the fourth column denotes gain factorsfor the signaled TFs, the fifth column denotes the number of physicalchannels (DPDCH) for the signaled TFs, and the sixth column denotesinitial coding rates of the signaled TFs. Here, when the number ofphysical channels is 6, TFI 13 is signaled so as to configure anothergain factor for TFs having higher initial coding rates. In the drawing,it is prearranged that TFI 13 is used as a reference TFI of TFs havingan initial coding rate of 0.5 or above.

As already described above, the signaled TFIs are regarded as referenceTFIs (RTFIs). In this way, only by signaling gain factors for some TFs,that is, TFI 0, TFI 4, TFI 6, TFI 9 and TFI 13, a UE can configure areference TF for each TF from TFI 0, a gain factor of which is notsignaled, to calculate its gain factor by using the reference TF.

FIG. 17 illustrates reference TFs configured in accordance with Example4 of the present invention.

Referring to FIG. 17, reference TFs of TFI 1 to TFI 3, that is,Ref_TFI_1 to Ref_TFI_3 are determined as TFI 0=RTFI(0) having the samenumber of physical channels. Similarly, a reference TF of TFI 5, thatis, Ref_TFI_5 is determined as TFI 4=RTFI(1) having the same number ofphysical channels, and reference TFs of TFI 7 and TFI 8, that is,Ref_TFI_7 and Ref_TFI_8 are determined as TFI 6=RTFI(2) having the samenumber of physical channels.

Although TFI 9 to TFI 17 have the same number of physical channels,there are two signaled TFIs, that is, TFI 9=RTFI(3) and TFI 13=RTFI(4).Here, according to prearranged mapping rules, reference TFs of TFI 14 toTFI 17 having initial coding rates of 0.5 or above, that is, Ref_TFI_14to Ref_TFI_17 are determined as TFI 13=RTFI(4), and reference TFs of TFI10 to TFI 12, that is, Ref_TFI_10 to Ref_TFI_12 are determined as TFI9=RTFI(3).

FIG. 18 is a flowchart illustrating an operation of a RNC in accordancewith Example 4 of the present invention. Here is shown an operation in acase where the first TF of TFs having the same number of physicalchannels is signaled as a reference TF.

Referring to FIG. 18, in step 602, a RNC repeats step 604 as many astimes corresponding to the number of TFs of the overall TF set whileincreases i one by one from 0, in order to generate information on gainfactors for the TFs of the overall TF set. Here, i is an integer equalto or greater than 0 and smaller than the number of TFs of the overallTF set.

First, in step 604, the RNC compares the number of physical channels foran i-th TF with that for a preceding TF, that is, an (i−1)-th TF. If thetwo number of physical channels are not the same as each other, the RNCproceeds to step 610. In a case of the first TF, the RNC directlyproceed to step 610 because there is no preceding TF. In step 610, theRNC include the i-th TF in gain factor information to be signaled to aUE. That is, the gain factor information comprises a gain factor for thei-th TF.

If the two number of physical channels are the same as each other instep 604, the RNC proceeds to step 606 to compare an initial coding rateof the i-th TF with a predetermined threshold, for example, 0.5. If theinitial coding rate of the i-th TF does not exceed 0.5, the RNC proceedsto step 608 not to include the gain factor of the i-th TF in the gainfactor information. In contrast, if the initial coding rate of the i-thTF exceeds 0.5, the RNC proceeds to step 610 to include the gain factorof the i-th TF in the gain factor information.

If the repetition operations for all the TFs of the TF set arecompleted, the RNC proceeds to step 612 to signal the gain factorinformation generated in step 602 to the UE. In other words, the RNCsignals gain factors for TFs, having the same number of physicalchannels as that of the preceding TFs and having initial coding gratedabove the threshold, to the UE.

Hereinafter, UE operation for preferably implementing Example 4 isdescribed.

A UE receives gain factor values for maxK TFs from a RNC through RRCsignaling. The signaled TFs are regarded as reference TFs. The UE checksif there is reference TFs having the same number of physical channels asthat of the respective TFs of the overall TF set. For example, if areference TF having the same number of physical channels as that ofTFI_i is one of the signaled TFs, that is, RTFI(k), the UE calculates again factor of TFI_i by applying a gain factor of RTFI(k) to Equation(4). In addition, if there are two reference TFs having the same numberof physical channels as that of TFI_i, that is, RTFI(k) and RTFI(k+1),the UE checks an initial coding rate of TFI_i. That is, if the initialcoding rate exceeds a predetermined threshold, the UE calculates thegain factor of TFI_i by using the signaled gain factor for an upperreference TF, that is, RTFI(k+1). In the preceding example, the UEcalculates the gain factors for TFs having initial coding rated above0.5 by using the gain factor of RTFI(4)=TFI 13. In contrast, if theinitial coding rate does not exceed the predetermined threshold, the UEcalculates the gain factor of TFI_i by using the signaled gain factorfor a lower reference TF, that is, RTFI(k).

According to the present invention as describe above, since a UE doesnot receive mapping information on reference TFs for all available TFs,but determines a reference TF for each TF according to predefined rules,upper signaling overhead required for signaling gain factors for a TFser can be reduced.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A method for configuring gain factors in a radio telecommunicationsystem, the method comprising the steps of: receiving one or more firstgain factors for first Transport Formats (TFs) corresponding to a partof a TF set including a plurality of TFs available for an uplinkservice; determining that one of the first TFs becomes a reference TF tobe used for at least one second TF other than the first TFs in the TFset by using a predefined rule; and calculating a second gain factor foreach second TF among the one or more second TFs by using the first gainfactor for the determined reference TF, the second gain factor beingused for transmitting or receiving uplink data. wherein the step ofdetermining, comprises the steps of determining that the first TF havingan index smaller than that of the second TF and is nearest to the secondTF, becomes the reference TF corresponding to the second TF.
 2. Themethod as claimed in claim 1, wherein the second gain factor iscalculated by means of the following equation,$\beta_{e,j} = {\beta_{e,{ref}}\sqrt{\frac{L_{ref}}{L_{j}}}\sqrt{\frac{N_{{info},j}}{N_{{info},{ref}}}}}$where, β_(e,j) denotes the second gain factor, β_(c,ref) denotes thefirst gain factor for the reference TF, L_(j) denotes the number ofphysical channels necessary for the second TF, L_(ref) denotes thenumber of physical channels necessary for the reference TF, N_(info,ref)denotes Transport Block (TB) size of the reference TF, and N_(info,j)denotes TB size of the second TF.
 3. The method as claimed in claim 1,wherein the step of determining, comprises the steps of determining thatthe first TF having an index greater than that of the second TF and isnearest to the second TF, becomes the reference TF corresponding to thesecond TF.
 4. The method as claimed in claim 3, wherein the second gainfactor is calculated by means of the following equation,$\beta_{e,j} = {\beta_{e,{ref}}\sqrt{\frac{L_{ref}}{L_{j}}}\sqrt{\frac{N_{{info},j}}{N_{{info},{ref}}}}}$where, β_(e,j) denotes the second gain factor, β_(e,ref) denotes thefirst gain factor for the reference TF, L_(j) denotes the number ofphysical channels necessary for the second TF, L_(ref) denotes thenumber of physical channels necessary for the reference TF, N_(info,ref)denotes TB size of the reference TF, and N_(info,j) denotes TB size ofthe second TF.
 5. The method as claimed in claim 1, wherein the step ofdetermining, comprises the steps of determining that the first TF isnearest to the second TF becomes the reference TF corresponding to thesecond TF.
 6. The method as claimed in claim 5, wherein the step ofdetermining, comprises the steps of determining that the first TF havinga smaller index between the two first TFs nearest to the second TFbecomes the reference TF corresponding to the second TF.
 7. The methodas claimed in claim 1, wherein the step of determining, comprises thesteps of determining that the first TF having the same number ofphysical channels as that of the second TF becomes the reference TFcorresponding to the second TF.
 8. The method as claimed in claim 1,wherein the step of determining comprises the steps of: determining thatthe first TF having an initial coding rate exceeding a predeterminedthreshold becomes the reference TF corresponding to the second TF, if aninitial coding rate of the second TF exceeds the predeterminedthreshold; and determining that the first TF having an initial codingrate not exceeding the predetermined threshold becomes the reference TFcorresponding to the second TF, if the initial coding rate of the secondTF does not exceed the predetermined threshold.
 9. The method as claimedin claim 1, wherein the first gain factors for the first TFs aresignaled from a Radio Network Controller (RNC) to a User Equipment (UE)and a Node B.